Question

Which one of the atoms shown would be most likely to form a cation with a charge of 1?

Answer 1

Ions are stable atoms of elements formed when original atoms loose or gain electrons to form stable configuration. Anions are negatively charged ions formed when atoms gain electrons while cations are the positively charged ions formed when atoms loose electrons. In this case a charge of +1 means an atom lost one electron to form a stable configuration. Therefore, the correct answer is A

Answer 2

If I am referring to correct picture then  
A. Has Four atoms in outer ring 
B. Has Five atoms in outer ring 
C. Has Six atoms in outer ring 
D. Has Seven atoms in outer ring 
E. Has Eight atoms in outer ring 
Answer is A 
Now we know that an atom wants to complete its outer shell while keeping electrons in pairs of two now in A there are four electrons which which can be ejected while in B will want to accept 3 electrons to complete its shell as ejecting five will take lot of energy similar case will be for C,D and E which would want to accept 2,1,0 electrons respectively